nonhabitable

Nonhabitable is an adjective used to describe places, environments, or worlds that cannot support sustained habitation by humans or other life forms, or cannot support long-term occupation. The term is formed from the prefix non- plus habitable, with habitable derived from Latin habitabilis, meaning capable of being lived in. In practice, nonhabitable is often used interchangeably with uninhabitable, though some contexts treat the terms differently. Some writers consider nonhabitable to emphasize the absence of necessary life-support conditions, while uninhabitable can stress the practical impossibility of living there.

In planetary science and astrobiology, nonhabitable environments describe worlds or regions that fail to meet the conditions typically required for life as known on Earth, such as stable liquid water, a breathable or otherwise life-sustaining atmosphere, and moderate temperatures. For example, the surfaces of the Moon and Mercury, and the extreme atmospheres or surfaces of Venus and the gas giants, are regarded as nonhabitable for humans, though they may harbor extremophiles or other life under certain assumptions.

In urban planning, architecture, and hazard assessment, nonhabitable can describe spaces or sites that are not suitable for living due to hazards, structural instability, contamination, or ongoing danger. This contrasts with places that are temporarily vacant or under renovation but could be inhabited with appropriate modifications.

Related terms include habitable and uninhabitable, with usage varying by discipline and region. See also habitability, the habitable zone in astronomy, and environmental suitability.